US Patent 10505517 Radio frequency switch circuit and apparatus having built-in coupler

A radio frequency switch circuit is described including a radio frequency switch and a coupler. The radio frequency switch includes a first band switch circuit connected between a first signal port and a common port, and configured to switch a first band signal. The coupler includes a first coupling wiring, disposed adjacent to a signal wiring formed between the common port of the radio frequency switch and an antenna port, and configured to form a first coupling signal with the signal wiring. A resonant frequency of the first coupling wiring is based on an inductance of the first coupling wiring and a capacitance of the radio frequency switch.